Effect of Tetrahydrofuran on the Optoelectronic Properties of PEDOT:PSS

Abstract

Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is an important conductive polymer. In its pristine form, however, its electrical conductivity is relatively low, which still cannot meet the requirements of practical applications. Solvent treatment is commonly used to improve its optoelectronic properties. Currently, while numerous experimental interpretations have been put forward regarding the mechanism driving the enhancement of optoelectronic properties induced by tetrahydrofuran (THF), the theoretical insights derived from simulations and modeling remain inadequate. In this work, spray coating was used to fabricate different PEDOT:PSS films, which contains pristine film, post-infiltration treatment film, post-drop-casting treatment film and solvent-treated film. We conducted simulations to replicate the intricate real world morphology of PEDOT:PSS, molecular dynamics (MD) simulation and density functional theory (DFT) simulation were employed to explain the modification mechanism of THF solvent-treated PEDOT:PSS thin films. We demonstrate that a certain degree of phase separation occurs between conductive PEDOT and insulating PSS after solvent treatment. PSS with high crystallinity dissolves extensively in polar organic solvents during dilution, leading to the aggregation of PEDOT, as well as increased interchain contact forces and charge transfer. Excess PSS is removed through the nanoscale phase separation induced by the addition of polar organic solvents.Enhance the overall optoelectronic performance.